Instead of trying to find a road wheel with the correct offset, it was decided to use the race wheels. The race car uses either Dymag or Speedline magnesium alloy wheels (sometimes a combination of both). The width of the race car rims vary slightly depending on the championship regulations. The project car uses slim front rims to ensure that the tyres arent struggling to get up to temperature. These wheels are centre locking and required the design of a custom Hub and Spindle Adapter. The adapter has two purposes:
1) as a spacer to account for the additional track and
2) to create the necessary spindle and locators for the centre lock wheel
The hub/spindle adapter design was stress analysed to confirm it was suitable for the application. It was then machined from billet before being anodised black.
The road tyre selection was rather limited, but some suitable Pirelli P-Zero Rosso were located (225x40ZR18 and 335x35ZR18). The locking nut is a Lotus special and is in fact made up of four parts
For track days there are set of spare rims with dry weather Dunlop slick tyres. The front rims are wider for this set and the tyre dimensions are 315/690/R18 compound 810 and 250/640/R18 compound 51.
It was decided that the existing AP Racing 4 pot callipers would be moved to the rear, and the fronts replaced by AP Racing 6 pot callipers. Moving the 4 pot to the rear also meant that it would need to be reversed to run at the front of the disc. This in turn required the fluid feed to be inverted. The callipers are mated with huge AP Racing grooved discs (356mm front and 330mm rear). The existing rear calliper was disconnected from the fluid circuit and used for the handbrake only.
One concern was the matching of the new brake callipers to the existing master cylinder. The match was discovered to be suitable with a very good balance between the front and rear brakes, without the use of any additional brake biasing.
The ABS can be switched out for track days.